BEGIN{
  prev=-1
  if (maxdiff=="") maxdiff=20000
  if (datacol=="") datacol=10
  FS=","
}
{
  curr=$datacol
  if (prev==-1) prev=curr
  diff=(curr>prev) ? (curr-prev) : (prev-curr)
  if (diff<maxdiff) print
  prev=curr
}
